On Thu, Aug 4, 2016 at 11:04 AM, Mkrtchyan, Tigran <tigran.mkrtchyan@xxxxxxx> wrote: > > Hi Olga et al. > > Finally I was able to to create a reproducer (attached)! > > It looks like, if on close client application is interrupted by > Ctrl+C or SIGINT, then nfs client does not sends CLOSE. I can > 100% reproduce it on RHEL7 and Fedora24 with 4.6 kernel. The 4.7 > kernel works (side effect of some other change?). > > The attached application reads file in a loop. On the second > iteration a thread is started, which will send SIGINT > to itself. When CLOSE is lost, you still can read the > file. Client even won't send any OPEN. So it looks like > that some where file is marked as open, but corresponding > process does not exist any more. Even re-mount does not help. > Thank you Tigran for a reproducer, I'll check it out and get back to you. > Best regards, > Tigran. > > ----- Original Message ----- >> From: "Olga Kornievskaia" <aglo@xxxxxxxxx> >> To: "Mkrtchyan, Tigran" <tigran.mkrtchyan@xxxxxxx> >> Cc: "Andy Adamson" <William.Adamson@xxxxxxxxxx>, "Linux NFS Mailing List" <linux-nfs@xxxxxxxxxxxxxxx>, "Trond Myklebust" >> <trond.myklebust@xxxxxxxxxxxxxxx>, "Steve Dickson" <steved@xxxxxxxxxx> >> Sent: Monday, August 1, 2016 11:22:10 PM >> Subject: Re: Lost CLOSE with NFSv4.1 on RHEL7 ( and bejond?) > >> On Mon, Aug 1, 2016 at 7:08 AM, Mkrtchyan, Tigran >> <tigran.mkrtchyan@xxxxxxx> wrote: >>> Hi Olga, >>> >>> we have installed kernel 4.7.0 on one of the nodes and don't see missing >>> closes from that node. >>> >>> Nevertheless, I don't think that the commit you have mentioned is fixing that, >>> as it fixes OPEN_DOWNGRADE, but we have a sequence of OPEN->CLOSE->OPEN. The >>> OPEN_DOWNGRADE is not expected - file is already closed when a second open >>> is sent and both requests using the same session slot. >>> >>> Have you seen a similar issue on vanilla or rhel kernel? >> >> I had a hard time triggering it consistently. I believe I have seen it >> on RHEL7.2 kernel but I think I was more consistently seeing it on >> some upstream (Trond's) kernel version (I think it was around 4.2). >> The problem was seen by Netapp QA on 4.3-rc7 version. >> >> Thanks for testing on the 4.7 version. I'll see what else went in that >> might explain the failure on the older kernel. >> >>> >>> Thanks a lot, >>> Tigran. >>> >>> ----- Original Message ----- >>>> From: "Olga Kornievskaia" <aglo@xxxxxxxxx> >>>> To: "Mkrtchyan, Tigran" <tigran.mkrtchyan@xxxxxxx> >>>> Cc: "Andy Adamson" <William.Adamson@xxxxxxxxxx>, "Linux NFS Mailing List" >>>> <linux-nfs@xxxxxxxxxxxxxxx>, "Trond Myklebust" >>>> <trond.myklebust@xxxxxxxxxxxxxxx>, "Steve Dickson" <steved@xxxxxxxxxx> >>>> Sent: Thursday, July 14, 2016 4:52:59 PM >>>> Subject: Re: Lost CLOSE with NFSv4.1 on RHEL7 ( and bejond?) >>> >>>> Hi Tigran, >>>> >>>> On Wed, Jul 13, 2016 at 12:49 PM, Mkrtchyan, Tigran >>>> <tigran.mkrtchyan@xxxxxxx> wrote: >>>>> >>>>> >>>>> Hi Andy, >>>>> >>>>> I will try to get upstream kernel on one of the nodes. It will take >>>>> some time as we need to add a new host into the cluster and get >>>>> some traffic go through it. >>>>> >>>>> In the mean while, with RHEL7 we get it easy reproduced - about 10 >>>>> such cases per day. Is there any tool that will help us to see where >>>>> it happens? Some traces points? Call trace from vfs close to NFS close? >>>> >>>> There are NFS tracepoints but I don't know think there are VFS >>>> tracepoints. Unfortunately, there was a bug in the OPEN tracepoints >>>> that caused a kernel crash. I had a bugzilla out for RHEL7.2. It says >>>> it's fixed in the later kernel (.381) but it's currently not back >>>> ported to RHEL7.2z but hopefully will be soon (just chatted with Steve >>>> about getting the fix into zstream). I made no progress in figuring >>>> out what could be causing the lack of CLOSE and it was hard for me to >>>> reproduce. >>>> >>>> Just recently Trond fixed a problem where a CLOSE that was suppose to >>>> be sent as an OPEN_DOWNGRADE wasn't sent (commit 0979bc2a59) . I >>>> wonder if that can be fixing this problem.... >>>> >>>>> There is a one comment in the kernel code, which sounds similar: >>>>> (http://git.linux-nfs.org/?p=trondmy/linux-nfs.git;a=blob;f=fs/nfs/nfs4proc.c;h=519368b987622ea23bea210929bebfd0c327e14e;hb=refs/heads/linux-next#l2955) >>>>> >>>>> nfs4proc.c: 2954 >>>>> ==== >>>>> >>>>> /* >>>>> * It is possible for data to be read/written from a mem-mapped file >>>>> * after the sys_close call (which hits the vfs layer as a flush). >>>>> * This means that we can't safely call nfsv4 close on a file until >>>>> * the inode is cleared. This in turn means that we are not good >>>>> * NFSv4 citizens - we do not indicate to the server to update the file's >>>>> * share state even when we are done with one of the three share >>>>> * stateid's in the inode. >>>>> * >>>>> * NOTE: Caller must be holding the sp->so_owner semaphore! >>>>> */ >>>>> int nfs4_do_close(struct nfs4_state *state, gfp_t gfp_mask, int wait) >>>>> >>>> >>>> I'm not sure if the comment means to say that there is a possibility >>>> that NFS won't send a CLOSE (or at least I hope not). I thought that >>>> because we keep a reference count on the inode and send the CLOSE when >>>> it goes down to 0. Basically the last WRITE will trigger the nfs close >>>> not the vfs_close. >>>> >>>> >>>>> ==== >>>>> >>>>> >>>>> Tigran. >>>>> >>>>> >>>>> ----- Original Message ----- >>>>>> From: "Andy Adamson" <William.Adamson@xxxxxxxxxx> >>>>>> To: "Mkrtchyan, Tigran" <tigran.mkrtchyan@xxxxxxx> >>>>>> Cc: "Linux NFS Mailing List" <linux-nfs@xxxxxxxxxxxxxxx>, "Andy Adamson" >>>>>> <William.Adamson@xxxxxxxxxx>, "Trond Myklebust" >>>>>> <trond.myklebust@xxxxxxxxxxxxxxx>, "Steve Dickson" <steved@xxxxxxxxxx> >>>>>> Sent: Tuesday, July 12, 2016 7:16:19 PM >>>>>> Subject: Re: Lost CLOSE with NFSv4.1 on RHEL7 ( and bejond?) >>>>> >>>>>> Hi Tigran >>>>>> >>>>>> Can you test with an upstream kernel? Olga has seen issues around no CLOSE being >>>>>> sent - it is really hard to reproduce…. >>>>>> >>>>>> —>Andy >>>>>> >>>>>> >>>>>>> On Jul 7, 2016, at 6:49 AM, Mkrtchyan, Tigran <tigran.mkrtchyan@xxxxxxx> wrote: >>>>>>> >>>>>>> >>>>>>> >>>>>>> Dear NFS folks, >>>>>>> >>>>>>> we observe orphan open-states on our deployment with nfsv4.1. >>>>>>> Our setup - two client nodes, running RHEL-7.2 with kernel >>>>>>> 3.10.0-327.22.2.el7.x86_64. Both nodes running ownCloud (like >>>>>>> a dropbox) which nfsv4.1 mounts to dCache storage. Some clients >>>>>>> connected to node1, others to node2. >>>>>>> >>>>>>> Time-to-time we see some 'active' transfers on data our DS >>>>>>> which do nothing. There is a corresponding state on MDS. >>>>>>> >>>>>>> I have traced one one such cases: >>>>>>> >>>>>>> - node1 uploads the file. >>>>>>> - node2 reads the file couple of times, OPEN+LAYOUTGET+CLOSE >>>>>>> - node2 sends OPEN+LAYOUTGET >>>>>>> - there is no open file on node2 which points to it. >>>>>>> - CLOSE never send to the server. >>>>>>> - node1 eventually removes the removes the file >>>>>>> >>>>>>> We have many other cases where file is not removed, but this one I was >>>>>>> able to trace. The link to capture files: >>>>>>> >>>>>>> https://desycloud.desy.de/index.php/s/YldowcRzTGJeLbN >>>>>>> >>>>>>> We had ~ 10^6 transfers in last 2 days and 29 files in such state (~0.0029%). >>>>>>> >>>>>> > Tigran. >>>>> -- >>>>> To unsubscribe from this list: send the line "unsubscribe linux-nfs" in >>>>> the body of a message to majordomo@xxxxxxxxxxxxxxx >>>>> More majordomo info at http://vger.kernel.org/majordomo-info.html >>>> -- >>>> To unsubscribe from this list: send the line "unsubscribe linux-nfs" in >>>> the body of a message to majordomo@xxxxxxxxxxxxxxx >>>> More majordomo info at http://vger.kernel.org/majordomo-info.html >> -- >> To unsubscribe from this list: send the line "unsubscribe linux-nfs" in >> the body of a message to majordomo@xxxxxxxxxxxxxxx >> More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
